首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   379篇
  免费   7篇
教育   291篇
科学研究   22篇
各国文化   19篇
体育   23篇
文化理论   2篇
信息传播   29篇
  2023年   2篇
  2022年   3篇
  2021年   2篇
  2020年   12篇
  2019年   13篇
  2018年   19篇
  2017年   19篇
  2016年   17篇
  2015年   11篇
  2014年   14篇
  2013年   70篇
  2012年   13篇
  2011年   13篇
  2010年   7篇
  2009年   9篇
  2008年   11篇
  2007年   11篇
  2006年   7篇
  2005年   8篇
  2004年   7篇
  2003年   5篇
  2002年   4篇
  2001年   12篇
  2000年   8篇
  1999年   7篇
  1998年   5篇
  1997年   5篇
  1996年   5篇
  1995年   13篇
  1994年   3篇
  1992年   3篇
  1990年   3篇
  1989年   5篇
  1988年   2篇
  1987年   3篇
  1986年   4篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1981年   2篇
  1979年   2篇
  1975年   2篇
  1973年   2篇
  1972年   2篇
  1968年   2篇
  1966年   1篇
  1918年   1篇
  1897年   1篇
  1895年   1篇
  1828年   1篇
排序方式: 共有386条查询结果,搜索用时 0 毫秒
381.
abstract

In the context of our work as literacy specialists, we taught teachers to use sentence frames to support ELL students’ writing. We then studied the impact of their instruction on students. Our analysis of student writing samples revealed no groupwide developmental trends so we posed deeper questions about their work using the data analysis methods learned through the action research process. We report our findings about the relationship between student writing development and language instruction. We discuss our learning as well as implications for our work supporting teacher instruction.  相似文献   
382.
Perception of kinetic illusory contours by 2-month-old infants was explored with sparse random-dot displays depicting an illusory shape against a background. In Experiment 1, 24 infants were habituated to a shape specified by accretion and deletion of background texture and relative motion, and exhibited a novelty preference when presented with luminance-defined familiar and novel shapes. Subsequent experiments explored kinetic cues in isolation. In Experiment 2 (n = 24), relative motion information was removed, leaving accretion and deletion of texture and luminance cues, and in Experiment 3 (n = 24), only relative motion information was available. In both these experiments the novelty preference obtained in Experiment 1 was replicated. Results from a control condition (n = 12) mitigated against the likelihood of an inherent preference for either of the test shapes. These findings reveal an early capacity to perceive shape solely from kinetic information, and suggest a mechanism geared toward spatiotemporal boundary formation that is functional shortly after birth. Theories of development of edge and motion discrimination are discussed.  相似文献   
383.
Alternating-current (AC) electrokinetics involve the movement and behaviors of particles or cells. Many applications, including dielectrophoretic manipulations, are dependent upon charge interactions between the cell or particle and the surrounding medium. Medium concentrations are traditionally treated as spatially uniform in both theoretical models and experiments. Human red blood cells (RBCs) are observed to crenate, or shrink due to changing osmotic pressure, over 10 min experiments in non-uniform AC electric fields. Cell crenation magnitude is examined as functions of frequency from 250 kHz to 1 MHz and potential from 10 Vpp to 17.5 Vpp over a 100 μm perpendicular electrode gap. Experimental results show higher peak to peak potential and lower frequency lead to greater cell volume crenation up to a maximum volume loss of 20%. A series of experiments are conducted to elucidate the physical mechanisms behind the red blood cell crenation. Non-uniform and uniform electrode systems as well as high and low ion concentration experiments are compared and illustrate that AC electroporation, system temperature, rapid temperature changes, medium pH, electrode reactions, and convection do not account for the crenation behaviors observed. AC electroosmotic was found to be negligible at these conditions and AC electrothermal fluid flows were found to reduce RBC crenation behaviors. These cell deformations were attributed to medium hypertonicity induced by ion concentration gradients in the spatially nonuniform AC electric fields.  相似文献   
384.
385.
386.
This study examined the association of gestational diabetes mellitus (GDM), prenatal, and postnatal maternal depressive symptoms with externalizing, internalizing, and autism spectrum problems on the Preschool Child Behavior Checklist in 2379 children aged 4.12 ± 0.60 (48% female; 47% White, 32% Black, 15% Mixed Race, 4% Asian, <2% American Indian/Alaskan Native, <2% Native Hawaiian; 23% Hispanic). Data were collected from the NIH Environmental influences on Child Health Outcomes (ECHO) Program from 2009-2021. GDM, prenatal, and postnatal maternal depressive symptoms were each associated with increased child externalizing and internalizing problems. GDM was associated with increased autism behaviors only among children exposed to perinatal maternal depressive symptoms above the median level. Stratified analyses revealed a relation between GDM and child outcomes in males only.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号